Currently ASG reports all the traffic/bandwidth usage that has gone through the device with source and destination ip, but not with the in and out interface.
This is the reason why there is no report to see how much traffic has gone over the interface at a given timeframe.

this could be usefull if your internet connection is billed volume.

Also the report like:
- table: in/out traffic of a specific interface (per day/week/month)
- chart: in/out traffic during the day over a specific interface
- dashboard: show total traffic flown in/out an interface today, not only realime bandwidth.